dog excessive want for food

Question
nine year old neutered male lab/beagle. very muscular dog, very strong and rather heavy. he never seems to be full. instead of "dog treats" he eats carrots. kibble down all the time and he gets a can of wet a day. he will eat i think until he bursts if i would let him. no excessive drinking, or lethargy or any other problems at all. he just never seems full at any time.

Answer
That behavior is quite typical of Labs, and maybe Beagles too. Tonight about 6:30 I asked my wife if she gave our 11 week old Lab her 6 PM feeding.  There was no telling by her behavior, or the 14 years old Lab that gets a token snack at each puppy feeding, that they had been fed 30 minutes ago.  Here is a link to one of our puppies about an hour before feeding time, http://www.photolocker.net/images/Labman/zekeandtheproplan.jpg

He may need to lose weight.  Your dog definitely should be narrower at the waist than the hips and chest.
You should be able to easily feel the ribs, but not see them.  Each dog is
different.  Standard recommendations are a good place to start, but each dog
must have its food adjusted to its individual needs. Here is a link to a good illustrated guide,
http://www.longliveyourdog.com/twoplus/RateYourDog.aspx